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UNIVERSITY OF VIRGINIA PUBLICATIONS 



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FiQ. 3. 



Chart, figure 3, gives another four-generation history of left-handedness 

 in the maternal line. Generation three shows the exact Mendelian pro- 

 portion for an RRxDR cross. But without further assumptions as to the 

 grandparents (generation two) of the paternal line, left-handedness would 

 here seem to be dominant. However, if the father may be regarded as a 

 heterozygote the numerically limited fourth generation is not necessarily 

 contrary to Mendelian expectation. Every possible effort is said to have 

 been made to break the children of the fourth generation of their left-handed- 

 ness but without success. 



A very interesting point in this connection is the fact that in the third 

 and fourth generations all the females were left-handed, all the males right- 

 handed. 



«*^ 



Fig. 4. 



• Chart, figure 4, shows a similar instance of apparently "sex-hmited" 

 heredity of lefthandedness. 



ii6^ 



Fig. 5. 



In chart, figure 5, on the contrary, all the males are left-handed, all 

 the females right-handed. This family knows of no left-handedness in 



* Not in the usual genetic sense. 



